Microstructural characteristics and mechanical properties of recycled K465 alloy with 50% return material addition ratio

The K465 master alloy incorporating 50% recycled material was prepared using vacuum induction melting. The as-cast microstructure of recycled K465 alloy was investigated through optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The room temperature tensile properties and high-temperature stress rupture performance after solution treatment were examined using a universal testing machine and creep testing machine. Results indicate that the as-cast microstructure of recycled K465 alloy primarily consists of γ matrix phase channels, γ' phase, (γ+γ') eutectic phase, and carbides. These carbides are MC-type carbides rich in Nb, Ti, Mo, and W. After solution treatment, the recycled alloy exhibits a room temperature tensile strength of 888 MPa with 7.5% elongation, and demonstrates a high-temperature stress rupture life of 832 hours and 16 minutes under 900 ℃/200 MPa conditions.